Nursing Elites

1. What is the process by which a cell divides into two or more new cells?

• A. Mitosis
• B. Meiosis
• C. Both mitosis and meiosis
• D. None of the above

Correct answer: A

Rationale: Mitosis is the process by which a cell divides into two identical daughter cells. This type of cell division is essential for growth, repair, and maintenance of multicellular organisms. Meiosis, on the other hand, is a type of cell division that produces gametes (sperm and egg cells) with half the number of chromosomes as the parent cell. Meiosis does not directly result in the formation of new cells, as it is specifically geared towards the production of reproductive cells. Therefore, the correct answer is A. Option C, stating both mitosis and meiosis, is incorrect because meiosis is not involved in the general process of cell division to produce new cells; it is specialized for gamete formation. Option D is incorrect because mitosis is indeed the process responsible for cell division in which one cell divides into two daughter cells, making it the accurate choice for this question.

2. Which of the following statements accurately characterizes the relationship between genes and chromosomes?

• A. Each gene contains multiple chromosomes.
• B. Each chromosome contains multiple genes.
• C. Genes and chromosomes are two different things referring to the same entity.
• D. Genes and chromosomes are not interchangeable terms and do not always occur in equal numbers.

Correct answer: B

Rationale: The correct answer is B: Each chromosome contains multiple genes. Genes, which are segments of DNA, are located on chromosomes and carry hereditary information. Chromosomes contain many genes, indicating that genes are part of the structure of chromosomes. Choice A is incorrect because genes do not contain chromosomes; rather, they are located on chromosomes. Choice C is incorrect as genes and chromosomes are distinct entities with different functions. Choice D is incorrect because genes and chromosomes are related but not in equal numbers; chromosomes contain multiple genes, but the number of genes can vary between chromosomes.

3. Which of the following is a special property of water?

• A. Water does not easily flow through phospholipid bilayers.
• B. A water molecule's oxygen atom does not allow fish to breathe.
• C. Water is highly cohesive, which explains its high melting point.
• D. Water cannot self-hydrolyze and decompose into hydrogen and oxygen.

Correct answer: C

Rationale: Water is highly cohesive, meaning it is attracted to itself due to its hydrogen bonding properties. This cohesion is the reason why water has a high melting point compared to other liquids of similar molecular weight. It is crucial for the existence of life on Earth as it allows water to remain a liquid within a wide range of temperatures, providing a stable environment for biological processes to occur. Choices A, B, and D are incorrect. Water's cohesive property does not directly relate to its ability to flow through phospholipid bilayers, assist fish in breathing, or self-hydrolyze into hydrogen and oxygen.

4. How do vaccines stimulate the immune system to develop memory without causing full-blown illness? What type of molecule in a vaccine typically triggers the immune response?

• A. Toxins produced by the pathogen
• B. Live, attenuated (weakened) forms of the pathogen
• C. Inactivated (dead) forms of the pathogen
• D. Antigens (specific molecules) from the pathogen

Correct answer: D

Rationale: Vaccines work by triggering the immune system to develop memory without causing illness. They typically contain antigens, which are specific molecules from the pathogen. These antigens stimulate the immune system to produce a targeted immune response without causing full-blown sickness. By presenting these antigens, vaccines help the immune system create memory cells that remember the pathogen. This memory allows the immune system to respond more effectively if it encounters the pathogen in the future. Choices A, B, and C are incorrect because vaccines do not typically contain toxins, live pathogens, or inactivated forms of the pathogen. Instead, vaccines primarily rely on specific molecules (antigens) to induce an immune response.

5. How does AIDS impair the immune system?

• A. AIDS targets and destroys Helper T-Cells, preventing the activation of Cytotoxic T-Cells or B-Cells.
• B. IgE stimulates mast cells to release excessive histamine.
• C. IgE inhibits mast cells from releasing sufficient histamine.
• D. Helper T-Cells deceive the body into attacking itself.

Correct answer: A

Rationale: AIDS targets and destroys Helper T-Cells, which play a crucial role in coordinating the immune response. By affecting these cells, AIDS prevents the activation of other important immune cells like Cytotoxic T-Cells or B-Cells. This disruption in the immune system's communication and response mechanisms leads to immune system failure and increased vulnerability to infections. Choices B and C are incorrect because they refer to the role of IgE in allergic reactions, which is not directly related to how AIDS impairs the immune system. Choice D is also incorrect as Helper T-Cells being destroyed in AIDS is not about deceiving the body into attacking itself, but rather the direct impact on immune system function.

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